5LC8

Crystal Structure of specific mutant from Pseudomonas aeruginosa Lipoxygenase at 1.8A resolution

Summary for 5LC8

• Entry DOI: 10.2210/pdb5lc8/pdb
• Descriptor: Arachidonate 15-lipoxygenase, FE (II) ION, GLYCEROL, ... (7 entities in total)
• Functional Keywords: non-heme iron enzyme, protein-phospholipid complex, oxidoreductase, a420g mutant, eicosanoids, infectious diseases, arachidonate 15s-lipoxygenase, linoleate 13s-lipoxygenase
• Biological source: Pseudomonas aeruginosa
• Total number of polymer chains: 1
• Total formula weight: 73809.29

Authors

Kalms, J.,Banthiya, S.,Galemou Yoga, E.,Kuhn, H.,Scheerer, P. (deposition date: 2016-06-20, release date: 2017-01-25, Last modification date: 2024-01-10)

Primary citation

Kalms, J.,Banthiya, S.,Galemou Yoga, E.,Hamberg, M.,Holzhutter, H.G.,Kuhn, H.,Scheerer, P.
The crystal structure of Pseudomonas aeruginosa lipoxygenase Ala420Gly mutant explains the improved oxygen affinity and the altered reaction specificity.
Biochim. Biophys. Acta, 1862:463-473, 2017

PubMed Abstract: Secreted LOX from Pseudomonas aeruginosa (PA-LOX) has previously been identified as arachidonic acid 15S-lipoxygenating enzyme. Here we report that the substitution of Ala420Gly in PA-LOX leads to an enzyme variant with pronounced dual specificity favoring arachidonic acid 11R-oxygenation. When compared with other LOX-isoforms the molecular oxygen affinity of wild-type PA-LOX is 1-2 orders of magnitude lower (Km O of 0.4mM) but Ala420Gly exchange improved the molecular oxygen affinity (Km O of 0.2mM). Experiments with stereo-specifically deuterated linoleic acid indicated that the formation of both 13S- and 9R-HpODE involves abstraction of the proS-hydrogen from C11 of the fatty acid backbone. To explore the structural basis for the observed functional changes (altered specificity, improved molecular oxygen affinity) we solved the crystal structure of the Ala420Gly mutant of PA-LOX at 1.8Å resolution and compared it with the wild-type enzyme. Modeling of fatty acid alignment at the catalytic center suggested that in the wild-type enzyme dioxygen is directed to C15 of arachidonic acid by a protein tunnel, which interconnects the catalytic center with the protein surface. Ala420Gly exchange redirects intra-enzyme O diffusion by bifurcating this tunnel so that C11 of arachidonic acid also becomes accessible for O insertion.

PubMed: 28093240
DOI: 10.1016/j.bbalip.2017.01.003

Experimental method

X-RAY DIFFRACTION (1.8 Å)